ASoC: samsung: arndale: Add missing OF node dereferencing

Ensure there is no OF node references kept when the driver
is removed/unbound.

Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20190920130218.32690-3-s.nawrocki@samsung.com


Signed-off-by: Mark Brown <broonie@kernel.org>